Expression of somatostatin type 2A receptor correlates with estrogen receptor in human breast carcinoma.

Somatostatin type 2A receptor (sstr2A) has been shown to be directly involved in the transduction of antiproliferative effects and also to be the most predominant sstr subtype in human normal breast epithelium, as well as in human breast carcinoma. We investigated the immunoreactivity of sstr2A in 34 cases of human breast carcinoma and correlated these findings with the immunoreactivity of the estrogen receptor (ER), epidermal growth factor receptor (EGFR), transforming growth factor alpha (TGFalpha) and insulin like growth factor I (IGF-I). We detected sstr2A immunoreactivity in normal mammary tissue, and in 27 of 34 (79%) breast carcinomas. The sstr2A immunoreactivity was localized on the cellular membrane, however, weak cytoplasmic immunoreactivity was also observed. Sstr2A immunoreactivity was heterogenously distributed in the whole tumor section. There was a statistically significant correlation between sstr2A and ER immunoreactivity in the same tumor. No statistically significant correlation was found between sstr2A immunoreactivity and immunoreactivity for EGFR, TGFalpha and IGF-I or the patients' age.